As of 2012, more than 1,800 publications dealing with ADHD genetics have been published, but unfortunately, no significant major genes have been identified and results are mainly inconclusive. Furthermore, the SNPs found by GWAS studies explain only a small part of the genetic variance.[PMID 23090882]

A 2009 meta-analysis of 75 separate studies found no association between ADHD and SNPs in the SLC6A4 or HTR1B genes. [PMID 19721846]

Many genes have been reported to influence susceptibility to ADHD, however slightly, and some may also affect the risk of substance abuse disorders. [PMID 18821565]

There is still controversy about ADHD: is it a normal variation with benefits that are currently not recognized, a treatable medical condition, or simply a diagnosis applied mainly to children who are younger than their classroom peers? For one news article on this controversy, see [1].